Write an equation to solve the problem.

two buses leave houston at the same time and travel in opposite directions. one bus averages 55 mi/h and the other bus averages 45 mi/h. when will they be 400 mi apart?

D=rtthe distances are not equal, but they add up to a total of 400 milesone bus goes 55mph times t so that is 55t (that represents the distance in one direction)the other bus goes 45 mph,so that is 45t (that represents the distance in the other direction)the total distance is 400, so the equation is distance one direction + distance the other direction = 400your equation is 55t + 45t = 400                         100t = 400                              t= 4 hoursso after 4 hours they will be 400 miles apart

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